Feathers act as aerodynamic cantilevers, and to withstand the prolonged cyclical loading that occurs during flight, feathers must be stiff, lightweight and strong. We experimentally tested the differences in feather structure, primarily stiffness and size, between (a) wild and captive Barnacle Geese Branta leucopsis, and (b) primary feathers dropped during the annual flight feather moult, and those feathers freshly regrown during the moult process. We found that, despite having undergone a 5,000km round-trip migration, flight feathers dropped during moult in the wild geese were stiffer than those measured in the captive geese, both for those dropped during moult and those re-grown. We propose that this may be related to diet or stress in the captive geese.

中文翻译：

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飞行羽毛的力学：囚禁的影响？

羽毛起到空气动力学悬臂的作用，并且要承受飞行过程中长时间出现的周期性载荷，羽毛必须坚硬，轻便且结实。我们通过实验测试了（a）野生的和圈养的藤壶鹅Branta leucopsis之间的羽毛结构差异，主要是硬度和大小，（b）在每年的飞行换羽过程中掉落的原生羽毛，以及在换羽过程中新鲜长出的那些羽毛。我们发现，尽管经历了5,000公里的往返迁移，但在换羽期间在野鹅中掉落的飞羽比在圈养鹅中测得的飞羽要坚硬，无论是换羽过程中掉落的鹅还是重新长大的。我们建议这可能与圈养鹅的饮食或压力有关。